1. Field of the Invention
The present invention relates to a process for producing 1-substituted tetrahydroquinazolines. More particularly, it relates to a process for producing 1-substituted tetrahydroquinazolines of formula (III) which comprises reacting tetrahydroquinazolines of formula (I) with hexamethyldisilazane; reacting the resultant product with a chloroalkanoate of formula (II) in the presence of an iodide of an alkaline metal; followed by desilylation.
2. Description of the Related Art
1-Substituted tetrahydroquinazoline of formula (III) are compounds known as intermediates for antiphlocgistics, and remedies for diabetic complications; it is also known that 1-substituted tetrahydroquinazolines of formula (III) are produced by reacting tetrahydroquinazolines of formula(I) with hexamethyldisilazane; reacting the resultant product with a bromoalkanoate; followed by desilylation (see, e.g., JP-A-64-25767).
However, this process is disadvantageous because expensive bromoalkanoate is used.
On the other hand, a process for producing 1-substituted tetrahydroquinazolines of formula (III) in which an inexpensive chloroalkanoate of formula (II) is used in place of the bromoalkanoate is also disadvantageous in that the yield is drastically lowered.
The present inventors have intensively studied the process for producing 1-substituted tetrahydroquinazolines of formula (III) so as to solve the above-mentioned drawbacks. As a result, it has been found, according to the present invention, that the desired product can be produced with high yield in an industrially advantageous manner, when the chloroalkanoate of formula (II) is used in place of the bromoalkanoate and the reaction is conducted in the presence of an iodide of an alkaline metal.